The Ghostbusters universe is coming back in full force with the new Paul Feig-directed reboot, and that includes all of the old ghost-repelling measures, such as the proton pack. In a new video, MIT particle physicist James Maxwell, who consulted on the new film, explains the surprisingly true-to-life science behind the classic ghostbusting weapon:

Maxwell was tasked with coming up with a scientific explanation (with "as few leaps of miraculous science as possible") for the proton pack, an energy weapon that fires a string of protons and polarizes the negatively charged energy of a ghost, weakening it and allowing it to be captured. In the original films, it was established that it works very much like a real-life particle collider, colliding high-energy positrons in order to generate a proton beam.

As Maxwell explains in the video, the original proton pack consists of a cyclotron, which is composed of two electrodes that induce the particle to spiral outwards from the center, accelerated by a rapidly varying electric field. Now, the proton packs will use a synchrotron, a descendant of the cyclotron which guides a particle down a closed path using a time-dependent magnetic field. Since a synchrotron requires very powerful magnetic fields, they would need a superconducting magnet, and a cryogen system to keep the magnets cold, which requires a source of helium.

Maxwell claims that all of the individual elements of a proton pack are real: "The real leaps of faith are actually doing it in the space that's allowed." So proton packs could technically exist, they would probably just be too big and heavy for Kristen Wiig, Ernie Hudson, Melissa McCarthy, or Bill Murray to look very cool wielding them.